diff --git a/static/css/cours.css b/static/css/cours.css
index 91d6cb1..1cd0239 100644
--- a/static/css/cours.css
+++ b/static/css/cours.css
@@ -48,4 +48,6 @@ aside li.directory {
 
 main img {
   max-width: 100%;
+  display: block;
+  margin: auto;
 }